U.S. patent number 10,998,796 [Application Number 16/514,367] was granted by the patent office on 2021-05-04 for structure for cooling rotating electrical machine and vehicle drive device.
This patent grant is currently assigned to AISIN AW CO., LTD., TOYOTA JIDOSHA KABUSHIKI KAISHA. The grantee listed for this patent is AISIN AW CO., LTD., TOYOTA JIDOSHA KABUSHIKI KAISHA. Invention is credited to Hiroto Hashimoto, Masayuki Ikemoto, Hiroshi Kato, Takefumi Komaki, Takuya Komatsu, Takashi Matsumoto, Satoshi Miyanaga, Yoshinari Nakagawa, Tomohito Ono.
United States Patent |
10,998,796 |
Ikemoto , et al. |
May 4, 2021 |
Structure for cooling rotating electrical machine and vehicle drive
device
Abstract
A structure for cooling a rotating electrical machine includes:
an oil pump, a supply oil passage connected to a discharge port of
the oil pump, and a first oil passage that is an oil passage
located above a stator of the rotating electrical machine in a
vertical direction and that has a supplied portion, a discharge
hole, and a discharge portion. The supplied portion is connected to
the supply oil passage. The discharge hole is formed on a first
side in an axial direction, which is one side in the axial
direction of the rotating electrical machine with respect to the
supplied portion and is configured to discharge oil toward the
stator. The discharge portion is formed on the first side with
respect to the discharge hole. A second oil passage is formed
inside a rotor shaft to which a rotor of the rotating electrical
machine is fixed, and a third oil passage connects the discharge
portion of the first oil passage and the second oil passage. The
third oil passage is formed along a first wall of the case which is
located on the first side with respect to the rotating electrical
machine.
Inventors: |
Ikemoto; Masayuki (Anjo,
JP), Komatsu; Takuya (Anjo, JP), Komaki;
Takefumi (Okazaki, JP), Kato; Hiroshi
(Nukata-gun, JP), Miyanaga; Satoshi (Okazaki,
JP), Nakagawa; Yoshinari (Nishio, JP), Ono;
Tomohito (Susono, JP), Hashimoto; Hiroto (Ebina,
JP), Matsumoto; Takashi (Toyota, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
AISIN AW CO., LTD.
TOYOTA JIDOSHA KABUSHIKI KAISHA |
Anjo
Toyota |
N/A
N/A |
JP
JP |
|
|
Assignee: |
AISIN AW CO., LTD. (Anjo,
JP)
TOYOTA JIDOSHA KABUSHIKI KAISHA (Toyota, JP)
|
Family
ID: |
1000005531996 |
Appl.
No.: |
16/514,367 |
Filed: |
July 17, 2019 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20200028412 A1 |
Jan 23, 2020 |
|
Foreign Application Priority Data
|
|
|
|
|
Jul 18, 2018 [JP] |
|
|
JP2018-135128 |
May 27, 2019 [JP] |
|
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JP2019-098474 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02K
9/19 (20130101); H02K 9/16 (20130101); H02K
9/193 (20130101) |
Current International
Class: |
H02K
9/16 (20060101); H02K 9/19 (20060101); H02K
9/193 (20060101) |
Field of
Search: |
;310/52-65 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Leung; Quyen P
Assistant Examiner: Chang; Minki
Attorney, Agent or Firm: Oliff PLC
Claims
What is claimed is:
1. A structure for cooling a rotating electrical machine
accommodated in a case, comprising: an oil pump; a supply oil
passage connected to a discharge port of the oil pump; a first oil
passage that is an oil passage located above a stator of the
rotating electrical machine in a vertical direction and that has a
supplied portion, a discharge hole, and a discharge portion, the
supplied portion being connected to the supply oil passage, the
discharge hole being formed on a first side in an axial direction,
which is one side in the axial direction of the rotating electrical
machine with respect to the supplied portion and being configured
to discharge oil toward the stator, the discharge portion being
formed on the first side with respect to the discharge hole; a
second oil passage formed inside a rotor shaft to which a rotor of
the rotating electrical machine is fixed; and a third oil passage
connecting the discharge portion of the first oil passage and the
second oil passage, the third oil passage being formed along a
first wall of the case, which is located on the first side in the
axial direction with respect to the rotating electrical
machine.
2. The structure according to claim 1, wherein: an end of the rotor
shaft on a second side in the axial direction is located on the
second side in the axial direction with respect to a second wall of
the case, which is located on the second side with respect to the
rotating electrical machine, the second side being an opposite side
in the axial direction from the first side.
3. The structure according to claim 2, wherein a connection portion
of the supply oil passage is formed along the second wall of the
case, the connection portion being a part of the supply oil passage
which is connected to the supplied portion.
4. The structure according to claim 3, wherein the supply oil
passage is formed by using a tubular member.
5. The structure according to claim 4, wherein: a first rotating
electrical machine and a second rotating electrical machine are
accommodated in the case, the second rotating electrical machine
being the rotating electrical machine; and the structure further
comprises: an oil cooler provided in the supply oil passage; and a
cooling oil passage through which oil for cooling the first
rotating electrical machine flows, the cooling oil passage being an
oil passage branching from a part of the supply oil passage, which
is located downstream of the oil cooler.
6. The structure according to claim 5, wherein the oil pump is
placed on a different axis from the rotating electrical
machine.
7. The structure according to claim 2, wherein the supply oil
passage is formed by using a tubular member.
8. The structure according to claim 2, wherein: a first rotating
electrical machine and a second rotating electrical machine are
accommodated in the case, the second rotating electrical machine
being the rotating electrical machine; and the structure further
comprises: an oil cooler provided in the supply oil passage; and a
cooling oil passage through which oil for cooling the first
rotating electrical machine flows, the cooling oil passage being an
oil passage branching from a part of the supply oil passage, which
is located downstream of the oil cooler.
9. The structure according to claim 1, wherein a connection portion
of the supply oil passage is formed along a second wall of the
case, which is located on a second side in the axial direction with
respect to the rotating electrical machine, the connection portion
being a part of the supply oil passage which is connected to the
supplied portion, and the second side being an opposite side in the
axial direction from the first side.
10. The structure according to claim 9, wherein the supply oil
passage is formed by using a tubular member.
11. The structure according to claim 9, wherein: a first rotating
electrical machine and a second rotating electrical machine are
accommodated in the case, the second rotating electrical machine
being the rotating electrical machine; and the structure further
comprises: an oil cooler provided in the supply oil passage; and a
cooling oil passage through which oil for cooling the first
rotating electrical machine flows, the cooling oil passage being an
oil passage branching from a part of the supply oil passage, which
is located downstream of the oil cooler.
12. The structure according to claim 1, wherein the supply oil
passage is formed by using a tubular member.
13. The structure according to claim 12, wherein: a first rotating
electrical machine and a second rotating electrical machine are
accommodated in the case, the second rotating electrical machine
being the rotating electrical machine; and the structure further
comprises: an oil cooler provided in the supply oil passage; and a
cooling oil passage through which oil for cooling the first
rotating electrical machine flows, the cooling oil passage being an
oil passage branching from a part of the supply oil passage, which
is located downstream of the oil cooler.
14. The structure according to claim 1, wherein: a first rotating
electrical machine and a second rotating electrical machine are
accommodated in the case, the second rotating electrical machine
being the rotating electrical machine; and the structure further
comprises: an oil cooler provided in the supply oil passage; and a
cooling oil passage through which oil for cooling the first
rotating electrical machine flows, the cooling oil passage being an
oil passage branching from a part of the supply oil passage, which
is located downstream of the oil cooler.
15. The structure according to claim 1, wherein the oil pump is
placed on a different axis from the rotating electrical
machine.
16. A vehicle drive device, comprising: the structure according to
claim 1; an output member drivingly coupled to a wheel; and a drive
transmission mechanism that transmits a driving force of the
rotating electrical machine to the output member; wherein the oil
pump is driven by rotation of the drive transmission mechanism.
17. The vehicle drive device according to claim 16, wherein the
rotating electrical machine is disposed so as to overlap the drive
transmission mechanism as viewed in the axial direction.
18. The vehicle drive device according to claim 17, wherein the
drive transmission mechanism is disposed on an opposite side in the
axial direction of the rotating electrical machine from the first
side.
Description
INCORPORATION BY REFERENCE
The disclosure of Japanese Patent Applications No. 2018-135128,
filed on Jul. 18, 2018, and No. 2019-098474, filed on May 27, 2019,
including the specification, drawings and abstract is incorporated
herein by reference in its entirety.
BACKGROUND
1. Related Technical Fields
Related technical fields include structures for cooling a rotating
electrical machine accommodated in a case and vehicle drive devices
having such a structure for cooling a rotating electrical
machine.
2. Description of the Related Art
Japanese Patent Application Publication No. 2015-89314 (JP
2015-89314 A) discloses an example of such a structure for cooling
a rotating electrical machine. In the following description of the
related art, reference characters in parentheses are those in JP
2015-89314 A. JP 2015-89314 A describes a structure for cooling a
motor (2) accommodated in a case (3). In this structure, a cooling
pipe (10) having a plurality of small holes (12) is placed adjacent
to a stator (22) within the case (3), and oil pumped from a pump
(31) is discharged toward the stator (22) through the small holes
(12) to cool the stator (22).
When cooling a rotating electrical machine, it is sometimes
desirable to be able to appropriately cool not only a stator but
also a rotor. For example, in the case where a rotating electrical
machine to be cooled is a permanent magnet rotating electrical
machine having a rotor with permanent magnets embedded in a rotor
core, irreversible demagnetization may occur if the temperature of
the permanent magnets becomes too high. It is therefore desirable
to be able to appropriately cool the rotor. The use of highly
coercive permanent magnets can avoid such irreversible
demagnetization. However, this causes an increase in cost as a rare
metal(s) needs to be added to permanent magnets in an amount large
enough to provide sufficient coercivity.
SUMMARY
Exemplary embodiments of the broad inventive principles described
herein provide a structure for cooling a rotating electrical
machine which can appropriately cool not only a stator but also a
rotor.
Exemplary embodiments provide a structure for cooling a rotating
electrical machine including an oil pump, a supply oil passage
connected to a discharge port of the oil pump, and a first oil
passage that is an oil passage located above a stator of the
rotating electrical machine in a vertical direction and that has a
supplied portion, a discharge hole, and a discharge portion. The
supplied portion is connected to the supply oil passage. The
discharge hole is formed on a first side in an axial direction,
which is one side in the axial direction of the rotating electrical
machine with respect to the supplied portion and is configured to
discharge oil toward the stator. The discharge portion is formed on
the first side with respect to the discharge hole. A second oil
passage is formed inside a rotor shaft to which a rotor of the
rotating electrical machine is fixed, and a third oil passage
connects the discharge portion of the first oil passage and the
second oil passage. The third oil passage is formed along a first
wall of the case which is located on the first side with respect to
the rotating electrical machine.
As such, oil in the first oil passage can be discharged toward the
stator through the discharge hole to cool the stator. Moreover, oil
can be made to flow through the second oil passage formed inside
the rotor shaft to cool the rotor.
Further, the structure includes the third oil passage connecting
the discharge portion of the first oil passage and the second oil
passage. A part of oil supplied from the supply oil passage to the
first oil passage can thus be supplied to the second oil passage
through the third oil passage to appropriately cool the rotor.
Since the oil passage for supplying oil to the second oil passage
and the oil passage for supplying oil to the first oil passage thus
have a common part, the oil passage configuration can be restrained
from becoming complex.
As described above, the structure for cooling a rotating electrical
machine can be implemented which can appropriately cool not only
the stator but also the rotor.
Further features and advantages of the structure for cooling a
rotating electrical machine will become apparent from the following
description of an embodiment given below with reference to the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Features, advantages, and technical and industrial significance of
exemplary embodiments will be described below with reference to the
accompanying drawings, in which like numerals denote like elements,
and wherein:
FIG. 1 is a sectional view of a vehicle drive device according to
an embodiment;
FIG. 2 is a partial enlarged view of FIG. 1;
FIG. 3 is a skeleton diagram of the vehicle drive device according
to the embodiment;
FIG. 4 is a diagram showing the positional relationship of parts of
the vehicle drive device according to the embodiment as viewed in
an axial direction; and
FIG. 5 is a simplified schematic of a hydraulic circuit according
to the embodiment.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
An embodiment of a structure for cooling a rotating electrical
machine and a vehicle drive device will be described with reference
to the accompanying drawings. In the embodiment described below, a
second stator 21 corresponds to the "stator," a second rotor 24
corresponds to the "rotor," a second rotor shaft 26 corresponds to
the "rotor shaft," a first discharge port 52a corresponds to the
"discharge port," a first supplied portion 91a corresponds to the
"supplied portion," a first discharge hole 91b corresponds to the
"discharge hole," a fourth oil passage 94 corresponds to the
"cooling oil passage," a second rotating electrical machine MG2
corresponds to the "rotating electrical machine," a first oil pump
OP1 corresponds to the "oil pump," and a third oil flow tube 43
corresponds to the "tubular member."
In the following description, the vertical direction V (see FIG. 4)
means the vertical direction in the state where a rotating
electrical machine to be cooled is in use. That is, the vertical
direction V means the vertical direction in the case where a
rotating electrical machine to be cooled is placed in the
orientation in which it is used. In the present embodiment, a
structure for cooling a rotating electrical machine is provided in
a vehicle drive device. The vertical direction V is therefore the
same as the vertical direction in the state where the vehicle drive
device is mounted on a vehicle. The terms "above" and "below" mean
the upper side and the lower side in the vertical direction V. In
the following description, the direction of each member refers to
the direction of that member in an assembled device (in the present
embodiment, the vehicle drive device) having a structure for
cooling a rotating electrical machine. The terms regarding the
dimensions, direction, position, etc. of each member are used as a
concept including variations due to tolerance (manufacturing
tolerance).
As used herein, the expression "drivingly coupled" means the state
where two rotary elements are coupled so that a driving force
(synonymous with torque) can be transmitted therebetween. This
concept includes the state where two rotary elements are coupled so
as to rotate together and the state where two rotary elements are
coupled via one or more transmission members so that a driving
force can be transmitted therebetween via the one or more
transmission members. Such transmission members include various
members that transmit rotation at the same speed or a shifted speed
(a shaft, a gear mechanism, a belt, a chain, etc.) and may include
engagement devices that selectively transmit rotation and a driving
force (a friction engagement device, a meshing engagement device,
etc.). In the case where the expression "drivingly coupled" is used
for rotary elements of a planetary gear mechanism, it refers to the
state where three rotary elements included in the planetary gear
mechanism are drivingly coupled to each other with no other rotary
elements interposed therebetween.
As used herein, the term "rotating electrical machine" is used as a
concept including a motor (electric motor), a generator (electric
generator), and a motor-generator that serves as either a motor or
a generator as necessary. As used herein, regarding arrangement of
two members, the expression "overlap each other as viewed in a
specific direction" means that when an imaginary line parallel to
the viewing direction is moved in each direction perpendicular to
the imaginary line, the imaginary line crosses both of the two
members in at least a part of the range where the imaginary line is
moved.
In the present embodiment, a structure for cooling a rotating
electrical machine is provided in a vehicle drive device 1. The
vehicle drive device 1 is a device that moves a vehicle by
transmitting the driving force of driving force sources (driving
force sources for wheels W) to output members 4 drivingly coupled
to the wheels W. As shown in FIG. 3, in the present embodiment, the
vehicle drive device 1 is a drive device (hybrid vehicle drive
device) for driving a vehicle (hybrid vehicle) having both an
internal combustion engine EG and a rotating electrical machine (in
this example, a first rotating electrical machine MG1 and a second
rotating electrical machine MG2) as driving force sources for the
wheels W. Specifically, the vehicle drive device 1 is what is
called a two-motor power-split hybrid vehicle drive device. The
internal combustion engine EG is a motor that is driven by fuel
combustion in the engine to output power (e.g., a gasoline engine,
a diesel engine, etc.).
The structure for cooling a rotating electrical machine according
to the present disclosure is a structure for cooling a rotating
electrical machine accommodated in a case. That is, the structure
for cooling a rotating electrical machine according to the present
disclosure is configured to cool a rotating electrical machine
accommodated in a case. In the present embodiment, as shown in FIG.
1, the structure for cooling a rotating electrical machine is
configured to cool the first rotating electrical machine MG1 and
the second rotating electrical machine MG2 which are accommodated
in a case 30. That is, in the present embodiment, the vehicle drive
device 1 includes a structure for cooling the first rotating
electrical machine MG1 and the second rotating electrical machine
MG2. Other devices or mechanisms included in the vehicle drive
device 1 are also accommodated in the case 30. In the present
embodiment, as shown in FIG. 3, the vehicle drive device 1
includes, in addition to the first rotating electrical machine MG1
and the second rotating electrical machine MG2, an input member 3,
the output members 4, a planetary gear mechanism PG, a counter gear
mechanism CG, an output differential gear unit DF, a first oil pump
OP1, and a second oil pump OP2. The input member 3, the output
members 4, the planetary gear mechanism PG, the counter gear
mechanism CG, the output differential gear unit DF, the first oil
pump OP1, and the second oil pump OP2 are also accommodated in the
case 30.
As shown in FIGS. 3 and 4, the first rotating electrical machine
MG1, the input member 3, the planetary gear mechanism PG, and the
second oil pump OP2 are placed on a first axis A1, the second
rotating electrical machine MG2 is placed on a second axis A2, the
output members 4 and the output differential gear unit DF are
placed on a third axis A3, the counter gear mechanism CG is placed
on a fourth axis A4, and the first oil pump OP1 is placed on a
fifth axis A5. The first axis A1, the second axis A2, the third
axis A3, the fourth axis A4, and the fifth axis A5 are axes
(imaginary axes) that are different from each other and located
parallel to each other. In the following description, the "axial
direction L" refers to the direction parallel to these axes (A1 to
A5) (i.e., the common axial direction of these axes). The "first
side L1 in the axial direction" refers to one side in the axial
direction L, and the "second side L2 in the axial direction" refers
to the other side in the axial direction L (i.e., the opposite side
in the axial direction L to the first side L1 in the axial
direction). In the present embodiment, the vehicle drive device 1
is mounted on the vehicle in such an orientation that the axial
direction L extends along a horizontal plane. In the present
embodiment, the vehicle drive device 1 is mounted on the vehicle in
such an orientation that the axial direction L extends in the
lateral direction of the vehicle.
As shown in FIG. 1, the first rotating electrical machine MG1
includes a first stator 11 and a first rotor 14. The first rotor 14
is supported so as to be rotatable relative to the first stator 11.
The first stator 11 includes a first stator core 12 and first coil
end portions 13. The first stator core 12 is fixed to the case 30.
The first stator core 12 has a coil wound therein, and the first
coil end portions 13 are parts of the coil which protrude from the
first stator core 12 in the axial direction L. The first stator 11
includes the first coil end portions 13 on both sides of the first
stator core 12 in the axial direction L. The first rotor 14 is
fixed to a first rotor shaft 16 and rotates with the first rotor
shaft 16. In the present embodiment, the first rotating electrical
machine MG1 is a permanent magnet rotating electrical machine (in
this example, an interior permanent magnet (IPM) synchronous
motor), and the first rotor 14 has a rotor core and permanent
magnets embedded in the rotor core. In the present embodiment, the
first rotating electrical machine MG1 is an inner rotor rotating
electrical machine, and the first rotor 14 is disposed radially
(about the first axis A1) inside the first stator core 12.
As shown in FIG. 1, the second rotating electrical machine MG2
includes the second stator 21 and the second rotor 24. The second
rotor 24 is supported so as to be rotatable relative to the second
stator 21. The second stator 21 includes a second stator core 22
and second coil end portions 23. The second stator core 22 is fixed
to the case 30. The second stator core 22 has a coil wound therein,
and the second coil end portions 23 are parts of the coil which
protrude from the second stator core 22 in the axial direction L.
The second stator 21 includes the second coil end portions 23 on
both sides in the axial direction L of the second stator core 22.
The second rotor 24 is fixed to the second rotor shaft 26 and
rotates with the second rotor shaft 26. In the present embodiment,
the second rotating electrical machine MG2 is a permanent magnet
rotating electrical machine (in this example, an IPM synchronous
motor), and the second rotor 24 has a rotor core and permanent
magnets embedded in the rotor core. In the present embodiment, the
second rotating electrical machine MG2 is an inner rotor rotating
electrical machine, and the second rotor 24 is disposed radially
(about the second axis A2) inside the second stator core 22.
The planetary gear mechanism PG includes a first rotary element 67,
a second rotary element 68, and a third rotary element 69. The
first rotary element 67 is drivingly coupled to the first rotating
electrical machine MG1, the second rotary element 68 is drivingly
coupled to the output members 4, and the third rotary element 69 is
drivingly coupled to the input member 3. In the present embodiment,
the first rotary element 67 is coupled to the first rotating
electrical machine MG1 (the first rotor shaft 16) so as to rotate
therewith, the second rotary element 68 is coupled to a
distribution output gear 64 so as to rotate therewith, and the
third rotary element 69 is coupled to the input member 3 so as to
rotate therewith. The distribution output gear 64 meshes with a
first gear 61, described below, of the counter gear mechanism CG.
The input member 3 is a member (in the present embodiment, a shaft
member) drivingly coupled to the internal combustion engine EG (an
output shaft such as a crankshaft). The input member 3 is coupled
to the internal combustion engine EG so as to rotate therewith or
is coupled to the internal combustion engine EG via other members
such as a damper and a clutch. The output members 4 are members
drivingly coupled to the wheels W. In the present embodiment, the
output members 4 are members that rotate with the wheels W. That
is, the output members 4 are members (e.g., side gears) in the
output differential gear unit DF which rotate with the wheels W or
members that form driveshafts coupling the output differential gear
unit DF and the wheels W.
In the present embodiment, the planetary gear mechanism PG is a
single-pinion type planetary gear mechanism. In the present
embodiment, the first rotary element 67 is a sun gear, the second
rotary element 68 is a ring gear, and the third rotary element 69
is a carrier. The planetary gear mechanism PG is thus configured to
distribute the torque of the internal combustion engine EG which is
transmitted to the third rotary element 69 to the first rotary
element 67 and the second rotary element 68 (i.e., distribute this
torque to the first rotating electrical machine MG1 and the output
members 4).
The counter gear mechanism CG includes the first gear 61, a second
gear 62, and a coupling shaft 63. The first gear 61 meshes with the
distribution output gear 64, the second gear 62 meshes with a
differential input gear 65 of the output differential gear unit DF.
The coupling shaft 63 couples the first gear 61 and the second gear
62. In the present embodiment, an output gear 60 of the second
rotating electrical machine MG2 also meshes with the first gear 61.
The output gear 60 is a gear for outputting the torque of the
second rotating electrical machine MG2 and is coupled to the second
rotor shaft 26 so as to rotate therewith. In the present
embodiment, the second rotor shaft 26 includes a first shaft member
26a and a second shaft member 26b which are coupled (in this
example, spline-coupled) to each other. The first shaft member 26a
is disposed so as to extend toward the first side L1 in the axial
direction from the joint portion between the first shaft member 26a
and the second shaft member 26b. The second shaft member 26b is
disposed so as to extend toward the second side L2 in the axial
direction from the joint portion between the first shaft member 26a
and the second shaft member 26b. The second rotor 24 is fixed to
the outer peripheral surface of the first shaft member 26a, and the
output gear 60 is formed on the outer peripheral surface of the
second shaft member 26b. In the present embodiment, the end of the
second rotor shaft 26 on the second side L2 in the axial direction
(in this example, the end of the second shaft member 26b on the
second side L2 in the axial direction) is located on the second
side L2 in the axial direction with respect to a second wall 32
described below. The output gear 60 is also located on the second
side L2 in the axial direction with respect to the second wall
32.
The output differential gear unit DF transmits the torque applied
to the differential input gear 65 by distributing this torque to
the pair of right and left output members 4 (i.e., distributing
this torque to the pair of right and left wheels W). For example,
the output differential gear unit DF is formed by using a bevel
gear type or planetary gear type differential gear mechanism.
The vehicle drive device 1 according to the present embodiment is
configured as described above. Accordingly, in a stepless shift
drive mode in which the torque of the internal combustion engine EG
is transmitted to the wheels W to move the vehicle, the first
rotating electrical machine MG1 outputs reaction torque to the
torque distributed to the first rotary element 67. At this time,
the first rotating electrical machine MG1 basically serves as a
generator and generates electricity by the torque distributed to
the first rotary element 67. Moreover, in the stepless shift drive
mode, the torque reduced from the torque of the internal combustion
engine EG is distributed to the second rotary element 68 as torque
for driving the wheels W, and the second rotating electrical
machine MG2 outputs torque so as to compensate for a shortfall in
required wheel torque (torque required to be transmitted to the
wheels W) as necessary. In an electric drive mode in which only the
torque of the second rotating electrical machine MG2 is transmitted
to the wheels W to move the vehicle, the internal combustion engine
EG is basically in a stopped state where fuel supply to the
internal combustion engine EG is stopped, and the first rotating
electrical machine MG1 is basically in an idle state (the state
where the first rotating electrical machine MG1 is controlled by
zero torque control so that its output torque becomes zero).
The vehicle drive device 1 includes a drive transmission mechanism
2 that transmits the driving force of the second rotating
electrical machine MG2 to the output members 4. In the present
embodiment, the drive transmission mechanism 2 includes the counter
gear mechanism CG and the output differential gear unit DF. In the
present embodiment, the second rotating electrical machine MG2 is
disposed so as to overlap the drive transmission mechanism 2 as
viewed in the axial direction L. Specifically, as shown in FIG. 4,
the second rotating electrical machine MG2 is disposed so as to
overlap the counter gear mechanism CG as viewed in the axial
direction L. In this example, the second rotating electrical
machine MG2 is disposed so as to overlap the fourth axis A4 on
which the counter gear mechanism CG is placed, as viewed in the
axial direction L. In FIG. 4, reference pitch circles are shown for
the gears, the outer shape of the first stator 11 (the outer shape
of the first stator core 12) is shown for the first rotating
electrical machine MG1, and the outer shape of the second stator 21
(the outer shape of the second stator core 22) is shown for the
second rotating electrical machine MG2.
In the present embodiment, as shown in FIG. 1, the drive
transmission mechanism 2 is disposed on the opposite side in the
axial direction L (the second side L2 in the axial direction) of
the second rotating electrical machine MG2 from the first side L1
in the axial direction. As described above, in the present
embodiment, the drive transmission mechanism 2 includes the counter
gear mechanism CG, and the counter gear mechanism CG is disposed on
the second side L2 in the axial direction with respect to the
second rotating electrical machine MG2. Specifically, the case 30
includes a first wall 31 and the second wall 32. The first wall 31
is located on the first side L1 in the axial direction with respect
to the second rotating electrical machine MG2, and the second wall
32 is located on the second side L2 in the axial direction with
respect to the second rotating electrical machine MG2. The first
wall 31 and the second wall 32 are support walls that support the
second rotor shaft 26. In this example, the case 30 further
includes a third wall 34, and the third wall 34 is located on the
second side L2 in the axial direction with respect to the second
wall 32. The third wall 34 is also a support wall that supports the
second rotor shaft 26. Specifically, the first shaft member 26a is
rotatably supported at two points in the axial direction L by the
first and second walls 31, 32, and the second shaft member 26b is
rotatably supported at two points in the axial direction L by the
second and third walls 32, 34. The counter gear mechanism CG is
disposed on the second side L2 in the axial direction with respect
to the second wall 32. The counter gear mechanism CG is also
disposed on the first side L1 in the axial direction with respect
to the third wall 34. In this example, the first wall 31 is located
on the first side L1 in the axial direction with respect to the
second rotating electrical machine MG2 so as to be adjacent to the
second rotating electrical machine MG2, and the second wall 32 is
located on the second side L2 in the axial direction with respect
to the second rotating electrical machine MG2 so as to be adjacent
to the second rotating electrical machine MG2. In the present
embodiment, the first wall 31 is a separate member from a
peripheral wall (a cylindrical wall surrounding the second rotating
electrical machine MG2 etc. as viewed in the axial direction L) of
the case 30 and is joined to the peripheral wall of the case 30
from the first side L1 in the axial direction so as to cover the
opening on the first side L1 in the axial direction of the
peripheral wall. That is, in the present embodiment, the first wall
31 is a cover member (specifically, a rear cover that covers the
opening on the opposite side of the peripheral wall from the side
on which the internal combustion engine EG is disposed).
As shown in FIG. 3, the vehicle drive device 1 includes the first
oil pump OP1. In the present embodiment, the first oil pump OP1 is
placed on a different axis from the second rotating electrical
machine MG2. The first oil pump OP1 may be placed coaxially with
the second rotating electrical machine MG2. Although not shown in
the figures, an oil reservoir portion for storing oil is formed in
the case 30. As shown in FIG. 5, the first oil pump OP1 sucks oil
from the oil reservoir portion through a first strainer ST1. As
shown in FIG. 3, in the present embodiment, the vehicle drive
device 1 further includes the second oil pump OP2. In the present
embodiment, the second oil pump OP2 is placed coaxially with the
first rotating electrical machine MG1. As shown in FIG. 5, the
second oil pump OP2 sucks oil from the oil reservoir portion
through a second strainer ST2. The first strainer ST1 and the
second strainer ST2 are filters for removing foreign matter
contained in oil. In this example, the first strainer ST1 that
filters oil sucked from the oil reservoir portion by the first oil
pump OP1 and the second strainer ST2 that filters oil sucked from
the oil reservoir portion by the second oil pump OP2 are separate
strainers. However, the first oil pump OP1 and the second oil pump
OP2 may be configured to suck oil from the oil reservoir portion
through a common strainer.
In the present embodiment, the first oil pump OP1 is driven by
rotation of the drive transmission mechanism 2. Specifically, the
first oil pump OP1 is configured to be driven by rotation of a
rotary member that is included in the drive transmission mechanism
2 and that is inseparably drivingly coupled to the wheels W (i.e.,
a rotary member that always rotates synchronously with the wheels
W). Accordingly, while the vehicle is moving, the first oil pump
OP1 can be driven regardless of whether the current drive mode is
the stepless shift drive mode or the electric drive mode (i.e.,
even while the internal combustion engine EG is stopped). In the
present embodiment, as shown in FIG. 3, the first oil pump OP1 is
configured to be driven by rotation of the differential input gear
65 of the output differential gear unit DF. Specifically, a first
pump drive shaft 53a, which is a drive shaft for the first oil pump
OP1, has a pump drive gear 66 thereon. As the pump drive gear 66
meshes with the differential input gear 65, the first oil pump OP1
is driven by rotation of the differential input gear 65.
The pump drive gear 66 may be configured to mesh with a gear (in
the present embodiment, the output gear 60, the first gear 61, or
the second gear 62) other than the differential input gear 65
included in the drive transmission mechanism 2 or to mesh with a
gear (in the present embodiment, the distribution output gear 64)
that meshes with the gear included in the drive transmission
mechanism 2 so that the first oil pump OP1 is driven by rotation of
the drive transmission mechanism 2. The first pump drive shaft 53a
and the rotary member included in the drive transmission mechanism
2 (or a rotary member that rotates synchronously with the rotary
member included in the drive transmission mechanism 2) may be
coupled via a wrapping transmission mechanism (a mechanism using a
chain and sprockets, a mechanism using a belt and pulleys, etc.) so
that the first oil pump OP1 is driven by rotation of the drive
transmission mechanism 2.
In the present embodiment, the second oil pump OP2 is driven by
rotation of the input member 3. Specifically, a second pump drive
shaft 53b, which is a drive shaft for the second oil pump OP2, is
coupled to the input member 3 so as to rotate therewith. As shown
in FIG. 2, the second pump drive shaft 53b is coupled to a pump
rotor 54 of the second oil pump OP2 so as to rotate therewith.
Accordingly, the second oil pump OP2 can be driven by the torque of
the internal combustion engine EG regardless of whether the vehicle
is moving or not. At least one of the first oil pump OP1 and the
second oil pump OP2 may be an electric oil pump that is driven by a
special electric motor exclusively for driving a pump.
Next, the structure for cooling a rotating electrical machine
according to the present embodiment will be specifically described.
As described below, the structure for cooling a rotating electrical
machine includes the first oil pump OP1, a supply oil passage 90, a
first oil passage 91, a second oil passage 92, and a third oil
passage 93, so that the second rotating electrical machine MG2 can
be cooled by oil discharged from the first oil pump OP1. That is,
the structure for cooling the second rotating electrical machine
MG2 includes the first oil pump OP1, the supply oil passage 90, the
first oil passage 91, the second oil passage 92, and the third oil
passage 93. In the present embodiment, the structure for cooling a
rotating electrical machine further includes a fourth oil passage
94, so that the first rotating electrical machine MG1 can be cooled
by oil discharged from the first oil pump OP1. In the present
embodiment, the structure for cooling a rotating electrical machine
further includes an oil cooler OC.
As shown in FIG. 5, the supply oil passage 90 is connected to a
first discharge port 52a, which is a discharge port of the first
oil pump OP1. In FIG. 5, the line representing the supply oil
passage 90 is shown thicker than the lines representing other oil
passages. In FIG. 5, the oil flow direction in each oil passage is
shown by arrow. In the present embodiment, the supply oil passage
90 includes a first discharge oil passage 81, a merged oil passage
83, and a downstream-side oil passage 84 in this order from the
upstream side. Specifically, the upstream-side end of the first
discharge oil passage 81 is connected to the first discharge port
52a, and the downstream-side end of the first discharge oil passage
81 is connected to the upstream-side end of the merged oil passage
83. The downstream-side end of the merged oil passage 83 is
connected to the upstream-side end of the downstream-side oil
passage 84, and the downstream-side end of the downstream-side oil
passage 84 is connected to the upstream-side end (a first supplied
portion 91a described below) of the first oil passage 91.
Accordingly, oil discharged from the first oil pump OP1
sequentially flows through the first discharge oil passage 81, the
merged oil passage 83, and the downstream-side oil passage 84 in
this order and is supplied to the first oil passage 91. A first
check valve 51a that does not allow oil to flow upstream is
disposed in the first discharge oil passage 81.
As described above, in the present embodiment, the vehicle drive
device 1 includes the second oil pump OP2 in addition to the first
oil pump OP1. In the present embodiment, the upstream-side end of a
second discharge oil passage 82 is connected to a second discharge
port 52b, which is a discharge port of the second oil pump OP2, and
the downstream-side end of the second discharge oil passage 82 is
connected to the upstream-side end of the merged oil passage 83.
That is, the merged oil passage 83 is an oil passage into which the
first discharge oil passage 81 and the second discharge oil passage
82 merge. A second check valve 51b that does not allow oil to flow
upstream is disposed in the second discharge oil passage 82.
As shown in FIG. 5, in the present embodiment, the oil cooler OC is
disposed in the supply oil passage 90. The oil cooler OC is a heat
exchanger that cools oil. For example, the oil cooler OC is a water
or air oil cooler. In the present embodiment, the oil cooler OC is
disposed in the merged oil passage 83. A relief valve RV (in the
present embodiment, two relief valves RV) is disposed in a part of
the merged oil passage 83 which is located upstream of the oil
cooler OC. When the oil pressure in the merged oil passage 83
becomes too high, the relief valve RV discharges a part of oil to
adjust the oil pressure in the merged oil passage 83.
As shown in FIG. 2, the first oil passage 91 is located above the
second stator 21 in the vertical direction V (see FIG. 4). The
first oil passage 91 has the first supplied portion 91a, first
discharge holes 91b, and a discharge portion 91c. The first
supplied portion 91a is connected to the supply oil passage 90 (in
the present embodiment, the downstream-side oil passage 84). The
first discharge holes 91b are formed on the first side L1 in the
axial direction with respect to the first supplied portion 91a and
discharge oil toward the second stator 21. The discharge portion
91c is formed on the first side L1 in the axial direction with
respect to the first discharge holes 91b. Oil supplied from the
supply oil passage 90 to the first oil passage 91 can thus be
discharged toward the second stator 21 through the first discharge
holes 91b to cool the second stator 21.
The first oil passage 91 is disposed so as to overlap the second
stator 21 as viewed in the vertical direction V. As shown in FIG.
2, in the present embodiment, the first oil passage 91 has the
first discharge hole 91b formed at a position overlapping the
second coil end portion 23 on the first side L1 in the axial
direction as viewed in the vertical direction V, the first
discharge hole 91b formed at a position overlapping the second coil
end portion 23 on the second side L2 in the axial direction as
viewed in the vertical direction V, and the first discharge hole
91b formed at a position overlapping the second stator core 22 as
viewed in the vertical direction V. Oil discharged through the
first discharge holes 91b can thus be supplied to the second stator
21 by a relatively simple configuration using gravity.
The first oil passage 91 is an oil passage whose both ends are the
first supplied portion 91a and the discharge portion 91c, and the
discharge portion 91c is located on the first side L1 in the axial
direction with respect to the first supplied portion 91a. The first
oil passage 91 thus extends at least between the first supplied
portion 91a and the discharge portion 91c in the axial direction L.
In the present embodiment, the first oil passage 91 does not have a
bent portion that reverses the oil flow from the first supplied
portion 91a toward the discharge portion 91c in the axial direction
L, and the first oil passage 91 is formed so as to extend uniformly
from the first supplied portion 91a to the discharge portion 91c
toward the first side L1 in the axial direction. That is, as the
oil flow direction in each oil passage is shown by arrow in FIG. 1,
oil flows toward the first side L1 in the axial direction in the
first oil passage 91. The first oil passage 91 may extend in a
direction parallel to the axial direction L or a direction tilted
with respect to the axial direction L.
As shown in FIG. 1, the second oil passage 92 is an oil passage
formed in the second rotor shaft 26 having the second rotor 24 of
the second rotating electrical machine MG2 fixed thereto. The
second rotor shaft 26 is formed by a cylindrical member extending
in the axial direction L, and the second oil passage 92 extending
in the axial direction L is formed by the space surrounded by the
inner peripheral surface of the second rotor shaft 26. The second
rotor 24 can thus be cooled by oil supplied to the second oil
passage 92. Oil flows toward the second side L2 in the axial
direction in the second oil passage 92. As described above, in the
present embodiment, the second rotor shaft 26 includes the first
shaft member 26a and the second shaft member 26b which are coupled
to each other. A part of the second oil passage 92 which is located
on the first side L1 in the axial direction is formed inside the
first shaft member 26a, and a part of the second oil passage 92
which is located on the second side L2 in the axial direction
formed inside the second shaft member 26b.
In the present embodiment, as shown in FIG. 1, the second rotor
shaft 26 (in this example, the first shaft member 26a) has a second
oil hole 72 that extends between the inner and outer peripheral
surfaces of the second rotor shaft 26 so as to provide
communication between the inside and outside of the second rotor
shaft 26. The second oil hole 72 is formed so as to extend through
a cylindrical portion of the second rotor shaft 26 in the radial
direction (the radial direction about the second axis A2; the same
applies to the following description in this paragraph). A second
rotor oil passage 25 is formed inside the second rotor 24 (the
rotor core of the second rotor 24). Although not described in
detail, the second rotor oil passage 25 has an axial oil passage
and a radial oil passage. The axial oil passage extends in the
axial direction L. The radial oil passage extends in the radial
direction between the inner peripheral surface of the second rotor
24 (the rotor core) and the axial oil passage so as to provide
communication between the space surrounded by the inner peripheral
surface of the second rotor 24 (the rotor core) and the axial oil
passage. Oil in the second oil passage 92 can thus be supplied to
the second rotor oil passage 25 through the second oil hole 72 to
cool the second rotor 24. In the present embodiment, the axial oil
passage of the second rotor oil passage 25 is formed so as to open
at both ends of the second rotor 24 (the rotor core) in the axial
direction L. Oil having cooled the second rotor 24 can thus be
supplied from inside in the radial direction to the second coil end
portions 23 to cool the second coil end portions 23.
As described above, the first oil pump OP1 is placed on a different
axis from the second rotating electrical machine MG2 (i.e., on a
different axis from the second rotor shaft 26). In this case,
depending on the configuration of the vehicle drive device 1, it
may be difficult, due to constraints on the space in the vehicle in
which the vehicle drive device 1 is mounted etc., to form an oil
passage directly connecting the first discharge port 52a of the
first oil pump OP1 and the second oil passage 92 formed inside the
second rotor shaft 26. In view of this, the structure for cooling a
rotating electrical machine has the third oil passage 93 connecting
the discharge portion 91c of the first oil passage 91 and the
second oil passage 92. The third oil passage 93 is formed along the
first wall 31 of the case 30 which is located on the first side L1
in the axial direction with respect to the second rotating
electrical machine MG2. Specifically, at least a part of the third
oil passage 93 is formed along the first wall 31. In the present
embodiment, the third oil passage 93 except for its upstream-side
and downstream-side ends is formed along the first wall 31. Since
the third oil passage 93 is thus formed along the first wall 31,
the third oil passage 93 for supplying oil discharged from the
first oil pump OP1 to the second oil passage 92 can be formed while
restraining an increase in size in the axial direction L of the
vehicle drive device 1 in the portion where the third oil passage
93 is formed (i.e., the portion where the second rotating
electrical machine MG2 is disposed).
In the present embodiment, as shown in FIGS. 1 and 2, a connection
portion 90a, namely a part of the supply oil passage 90 which is
connected to the first supplied portion 91a, is formed along the
second wall 32 of the case 30 which is located on the second side
L2 in the axial direction with respect to the second rotating
electrical machine MG2. The connection portion 90a is a part
including the downstream-side end of the supply oil passage 90 (in
the present embodiment, the downstream-side oil passage 84), and at
least a part of the connection portion 90a is formed along the
second wall 32.
As shown in FIG. 1, in the present embodiment, the third oil
passage 93 is formed inside the first wall 31. At least a part of
the third oil passage 93 may be formed outside the first wall 31
(e.g., may be formed inside a tubular member attached to the first
wall 31 from the second side L2 in the axial direction). In the
present embodiment, the first wall 31 has a second connection
portion 33b. The second connection portion 33b has a cylindrical
shape protruding toward the second side L2 in the axial direction,
and the opening on the second side L2 in the axial direction of the
second connection portion 33b is located inside the second rotor
shaft 26. The downstream-side end of the third oil passage 93 is
formed by the space surrounded by the inner peripheral surface of
the second connection portion 33b. The downstream-side end of the
third oil passage 93 and the upstream-side end of the second oil
passage 92 are thus connected in the second connection portion
33b.
In the present embodiment, the structure for cooling a rotating
electrical machine further includes the fourth oil passage 94
through which oil for cooling the first rotating electrical machine
MG1 flows. As shown in FIG. 5, the fourth oil passage 94 is formed
so as to branch from a part of the supply oil passage 90 which is
located downstream of the oil cooler OC. Oil cooled by the oil
cooler OC can thus be supplied not only to the first oil passage 91
and the second oil passage 92 but also to the fourth oil passage
94.
As shown in FIG. 2, the fourth oil passage 94 is located above the
first stator 11 in the vertical direction V (see FIG. 4). The
fourth oil passage 94 has a second supplied portion 94a and second
discharge holes 94b. The second supplied portion 94a is connected
to an intermediate part of the supply oil passage 90 (in the
present embodiment, the downstream-side end of the merged oil
passage 83, namely the upstream-side end of the downstream-side oil
passage 84). The second discharge holes 94b are formed on the first
side L1 in the axial direction with respect to the second supplied
portion 94a and discharge oil toward the first stator 11. Oil
supplied from the supply oil passage 90 to the fourth oil passage
94 can thus be discharged toward the first stator 11 through the
second discharge holes 94b to cool the first stator 11.
The fourth oil passage 94 is disposed so as to overlap the first
stator 11 as viewed in the vertical direction V. As shown in FIG.
2, in the present embodiment, the fourth oil passage 94 has the
second discharge hole 94b formed at a position overlapping the
first coil end portion 13 on the first side L1 in the axial
direction as viewed in the vertical direction V, the second
discharge hole 94b formed at a position overlapping the first coil
end portion 13 on the second side L2 in the axial direction as
viewed in the vertical direction V, and the second discharge hole
94b formed at a position overlapping the first stator core 12 as
viewed in the vertical direction V. Oil discharged through the
second discharge holes 94b can thus be supplied to the first stator
11 by a relatively simple configuration using gravity.
As shown in FIGS. 2 and 5, in the present embodiment, the structure
for cooling a rotating electrical machine further includes a fifth
oil passage 95. As shown in FIG. 2, the fifth oil passage 95 is an
oil passage formed inside the second pump drive shaft 53b. The
second pump drive shaft 53b is formed by a cylindrical member
extending in the axial direction L, and the fifth oil passage 95
extending in the axial direction L is formed by the space
surrounded by the inner peripheral surface of the second pump drive
shaft 53b. As shown in FIG. 5, the fifth oil passage 95 is formed
so as to branch from a part of the second discharge oil passage 82
which is located upstream of the second check valve 51b. The amount
of oil that flows from the second discharge oil passage 82 into the
fifth oil passage 95 is controlled by a second orifice 50b.
Oil flows toward the second side L2 in the axial direction in the
fifth oil passage 95. As shown in FIG. 5, oil in the fifth oil
passage 95 is supplied to the first rotating electrical machine MG1
(the first rotor 14) for cooling and is also supplied to the
planetary gear mechanism PG for lubrication. Specifically, as shown
in FIG. 2, the first rotor shaft 16 is formed by a cylindrical
member extending in the axial direction L, and the second pump
drive shaft 53b is disposed in the space surrounded by the inner
peripheral surface of the first rotor shaft 16. The second pump
drive shaft 53b has a third oil hole 73 that extends between the
inner and outer peripheral surfaces of the second pump drive shaft
53b so as to provide communication between the inside and outside
of the second pump drive shaft 53b. The third oil hole 73 is formed
so as to extend through a cylindrical portion of the second pump
drive shaft 53b in the radial direction (the radial direction about
the first axis A1; the same applies to the following description in
this paragraph). The first rotor shaft 16 has a first oil hole 71
that extends between the inner and outer peripheral surfaces of the
first rotor shaft 16 so as to provide communication between the
inside and outside of the first rotor shaft 16. The first oil hole
71 is formed so as to extend through a cylindrical portion of the
first rotor shaft 16 in the radial direction. A first rotor oil
passage 15 is formed inside the first rotor 14 (the rotor core of
the first rotor 14). Although not described in detail, the first
rotor oil passage 15 includes an axial oil passage and a radial oil
passage. The axial oil passage extends in the axial direction L.
The radial oil passage extends in the radial direction between the
inner peripheral surface of the first rotor 14 (the rotor core) and
the axial oil passage so as to provide communication between the
space surrounded by the inner peripheral surface of the first rotor
14 (the rotor core) and the axial oil passage.
Oil in the fifth oil passage 95 can thus be supplied to the inner
peripheral surface of the first rotor shaft 16 through the third
oil hole 73 and the oil supplied to the inner peripheral surface of
the first rotor shaft 16 can be supplied to the first rotor oil
passage 15 through the first oil hole 71 to cool the first rotor
14. In the present embodiment, the axial oil passage of the first
rotor oil passage 15 is formed so as to open at both ends of the
first rotor 14 (the rotor core) in the axial direction L. Oil
having cooled the first rotor 14 can therefore be supplied from
inside in the radial direction (the radial direction about the
first axis A1) to the first coil end portions 13 to cool the first
coil end portions 13. Oil in the fifth oil passage 95 also flows
into an oil passage formed inside the input member 3 and is then
supplied through a fourth oil hole 74 (see FIGS. 1 and 2) formed in
the input member 3 to the planetary gear mechanism PG etc. for
lubrication.
As shown in FIG. 5, in the present embodiment, the structure for
cooling a rotating electrical machine further includes a sixth oil
passage 96. The sixth oil passage 96 is formed so as to branch from
a part of the first discharge oil passage 81 which is located
upstream of the first check valve 51a. Oil in the sixth oil passage
96 is supplied to the counter gear mechanism CG and the output
differential gear unit DF for lubrication. The amount of oil that
flows from the first discharge oil passage 81 into the sixth oil
passage 96 is controlled by a first orifice 50a.
As shown in FIGS. 1 and 2, in the present embodiment, the vehicle
drive device 1 includes a tubular first oil flow tube 41, a tubular
second oil flow tube 42, and a tubular third oil flow tube 43. The
fourth oil passage 94 is formed inside the first oil flow tube 41,
the first oil passage 91 is formed inside the second oil flow tube
42, and the downstream-side oil passage 84 is formed inside the
third oil flow tube 43. That is, in the present embodiment, the
supply oil passage 90 is formed by using the third oil flow tube 43
that is a tubular member. Specifically, the downstream-side oil
passage 84 included in the supply oil passage 90 is formed by using
the third oil flow tube 43 that is a tubular member. As shown in
FIG. 1, in the present embodiment, the first wall 31 has a first
connection portion 33a having a cylindrical shape protruding toward
the second side L2 in the axial direction, and the upstream end of
the third oil passage 93 is formed by the space surrounded by the
inner peripheral surface of the first connection portion 33a. The
second oil flow tube 42 is disposed such that the discharge portion
91c is connected to the first connection portion 33a. The
downstream-side end (the discharge portion 91c) of the first oil
passage 91 and the upstream-side end of the third oil passage 93
are thus connected in the first connection portion 33a. The second
oil flow tube 42 is disposed such that its both ends are located at
different positions in the axial direction L (e.g., is disposed so
as to extend in the axial direction L), and the discharge portion
91c of the first oil passage 91 is formed by the opening on the
first side L1 in the axial direction of the second oil flow tube
42. The first discharge holes 91b are formed so as to extend
through a cylindrical portion of the second oil flow tube 42.
As shown in FIG. 2, in the present embodiment, the second wall 32
includes a third connection portion 33c having a cylindrical shape
extending in the axial direction L. The end of the second oil flow
tube 42 on the second side L2 in the axial direction is fitted in
the third connection portion 33c from the first side L1 in the
axial direction, and an end of the third oil flow tube 43 is fitted
in the third connection portion 33c from the second side L2 in the
axial direction. The downstream-side end of the downstream-side oil
passage 84 and the upstream-side end (the first supplied portion
91a) of the first oil passage 91 are thus connected in the third
connection portion 33c. The first supplied portion 91a of the first
oil passage 91 is formed by the opening on the second side L2 in
the axial direction of the second oil flow tube 42.
As shown in FIG. 2, in the present embodiment, the second wall 32
includes a fourth connection portion 33d having a cylindrical shape
extending in the axial direction L. The end of the first oil flow
tube 41 on the second side L2 in the axial direction is fitted in
the fourth connection portion 33d from the first side L1 in the
axial direction, and an end (the opposite end from the end
connected to the third connection portion 33c) of the third oil
flow tube 43 is fitted in the fourth connection portion 33d from
the second side L2 in the axial direction. The downstream-side end
of the merged oil passage 83 is formed so as to open to the inner
peripheral surface of the fourth connection portion 33d. The
downstream-side end of the merged oil passage 83, the upstream-side
end of the downstream-side oil passage 84, and the upstream-side
end (the second supplied portion 94a) of the fourth oil passage 94
are thus connected in the fourth connection portion 33d. The first
oil flow tube 41 is disposed such that its both ends are located at
different positions in the axial direction L (e.g., is disposed so
as to extend in the axial direction L), and the second supplied
portion 94a of the fourth oil passage 94 is formed by the opening
on the second side L2 in the axial direction of the first oil flow
tube 41. The second discharge holes 94b are formed so as to extend
through a cylindrical portion of the first oil flow tube 41.
OTHER EMBODIMENTS
Other embodiments of the structure for cooling a rotating
electrical machine and the vehicle drive device will be described
below.
(1) The configuration of the hydraulic circuit (see FIG. 5)
described in the above embodiment is merely illustrative and may be
modified as appropriate. For example, the above embodiment is
described with respect to the configuration in which the fourth oil
passage 94 is formed so as to branch from the supply oil passage
90. However, the fourth oil passage 94 may be connected to the
second discharge oil passage 82 without the supply oil passage 90
interposed therebetween. That is, oil discharged from the first oil
pump OP1 may be supplied only to the second rotating electrical
machine MG2 out of the first and second rotating electrical
machines MG1, MG2. In this case, the second discharge oil passage
82 may not be merged with the supply oil passage 90. The above
embodiment is described with respect to the configuration in which
the vehicle drive device 1 includes the second oil pump OP2 in
addition to the first oil pump OP1. However, the vehicle drive
device 1 may include only the first oil pump OP1 out of the first
and second oil pumps OP1, OP2.
(2) The above embodiment is described with respect to the
configuration in which the connection portion 90a, namely a part of
the supply oil passage 90 which is connected to the first supplied
portion 91a, is formed along the second wall 32. However, the
present disclosure is not limited to this configuration. The
connection portion 90a may not be formed along the second wall
32.
(3) The above embodiment is described with respect to the
configuration in which the second rotating electrical machine MG2
is disposed so as to overlap the drive transmission mechanism 2
(specifically, the counter gear mechanism CG) as viewed in the
axial direction L. However, the present disclosure is not limited
to this configuration. For example, the second rotating electrical
machine MG2 may be disposed at a different position from the
counter gear mechanism CG as viewed in the axial direction L so as
not to overlap the counter gear mechanism CG as viewed in the axial
direction L. The above embodiment is described with respect to the
configuration in which the drive transmission mechanism 2 is
disposed on the second side L2 in the axial direction with respect
to the second rotating electrical machine MG2. However, the present
disclosure is not limited to this configuration. At least a part of
the drive transmission mechanism 2 (e.g., the counter gear
mechanism CG) may be disposed on the first side L1 in the axial
direction with respect to the second rotating electrical machine
MG2.
(4) The configuration of the vehicle drive device 1 described in
the above embodiment is merely illustrative and may be modified as
appropriate. For example, the vehicle drive device 1 may not
include the counter gear mechanism CG, and the distribution output
gear 64 and the output gear 60 of the second rotating electrical
machine MG2 may mesh with the differential input gear 65. In this
case, unlike the above embodiment, the drive transmission mechanism
2 does not include the counter gear mechanism CG. The vehicle drive
device 1 may not include the output differential gear unit DF, and
the vehicle drive device 1 may transmit the driving force of the
driving force sources for the wheels W to a single output member 4
instead of the pair of right and left output members 4 (that is,
may transmit the driving force of the driving force sources for the
wheels W to a single wheel W instead of the pair of right and left
wheels W). In this case, unlike the above embodiment, the drive
transmission mechanism 2 does not include the output differential
gear unit DF.
(5) The above embodiment is described with respect to the
configuration in which the vehicle drive device 1 is a drive device
for driving a vehicle having both the internal combustion engine EG
and the rotating electrical machines as driving force sources for
the wheels W. However, the present disclosure is not limited to
this configuration. The vehicle drive device 1 may be a drive
device for driving a vehicle that does not include the internal
combustion engine EG as a driving force source for the wheels W.
For example, the vehicle drive device 1 may be a drive device for
driving an electric vehicle (electric car) having only one or more
rotating electrical machines as a driving force source(s) for the
wheels W.
(6) The above embodiment is described with respect to the
configuration in which the vehicle drive device 1 includes the
first rotating electrical machine MG1 and the second rotating
electrical machine MG2, and the structure for cooling a rotating
electrical machine which is included in the vehicle drive device 1
is a structure for cooling the first rotating electrical machine
MG1 and the second rotating electrical machine MG2. However, the
present disclosure is not limited to this configuration. The
vehicle drive device 1 may include only the second rotating
electrical machine MG2 out of the first and second rotating
electrical machines MG1, MG2, and the structure for cooling a
rotating electrical machine which is included in the vehicle drive
device 1 may be a structure for cooling the second rotating
electrical machine MG2.
(7) The above embodiment is described with respect to the
configuration in which the structure for cooling a rotating
electrical machine is provided in the vehicle drive device 1.
However, the present disclosure is not limited to this
configuration. The structure for cooling a rotating electrical
machine according to the present disclosure may be provided in a
device or equipment other than the vehicle drive device.
(8) The configuration disclosed in each of the above embodiments
may be combined with any of the configurations disclosed in the
other embodiments (including combinations of the embodiments
described as "Other Embodiments") unless inconsistency arises.
Regarding other configurations as well, the embodiments disclosed
in the specification are merely illustrative in all respects.
Accordingly, various alterations can be made as appropriate without
departing from the spirit and scope of the present disclosure.
Summary of Embodiments
The summary of the structure for cooling a rotating electrical
machine and the vehicle drive device described above will be
provided.
A structure for cooling a rotating electrical machine (MG2)
accommodated in a case (30) includes: an oil pump (OP1); a supply
oil passage (90) connected to a discharge port (52a) of the oil
pump (OP1); a first oil passage (91) that is an oil passage located
above a stator (21) of the rotating electrical machine (MG2) in a
vertical direction (V) and that has a supplied portion (91a), a
discharge hole (91b), and a discharge portion (91c), the supplied
portion (91a) being connected to the supply oil passage (90), the
discharge hole (91b) being formed on a first side (L1) in an axial
direction, which is one side in the axial direction (L) of the
rotating electrical machine (MG2), with respect to the supplied
portion (91a) and being configured to discharge oil toward the
stator (21), and the discharge portion (91c) being formed on the
first side (L1) in the axial direction with respect to the
discharge hole (91b); a second oil passage (92) formed inside a
rotor shaft (26) to which a rotor (24) of the rotating electrical
machine (MG2) is fixed; and a third oil passage (93) connecting the
discharge portion (91c) of the first oil passage (91) and the
second oil passage (92). The third oil passage (93) is formed along
a first wall (31) of the case (30), which is located on the first
side (L1) in the axial direction with respect to the rotating
electrical machine (MG2).
With the above configuration, oil in the first oil passage (91) can
be discharged toward the stator (21) through the discharge hole
(91b) to cool the stator (21). Moreover, oil can be made to flow
through the second oil passage (92) formed inside the rotor shaft
(26) to cool the rotor (24).
With the above configuration, the structure for cooling the
rotating electrical machine (MG2) includes the third oil passage
(93) connecting the discharge portion (91c) of the first oil
passage (91) and the second oil passage (92). A part of oil
supplied from the supply oil passage (90) to the first oil passage
(91) can thus be supplied to the second oil passage (92) through
the third oil passage (93) to appropriately cool the rotor (24).
Since the oil passage for supplying oil to the second oil passage
(92) and the oil passage for supplying oil to the first oil passage
(91) thus have a common part, the oil passage configuration can be
restrained from becoming complex.
As described above, according to the above configuration, the
structure for cooling the rotating electrical machine (MG2) can be
implemented which can appropriately cool not only the stator (21)
but also the rotor (24).
An end of the rotor shaft (26) on a second side (L2) in the axial
direction may be located on the second side (L2) in the axial
direction with respect to a second wall (32) of the case (30) which
is located on the second side (L2) in the axial direction with
respect to the rotating electrical machine (MG2), the second side
(L2) in the axial direction being an opposite side in the axial
direction (L) from the first side (L1) in the axial direction.
In the above configuration, the end of the rotor shaft (26) on the
second side (L2) in the axial direction is located on the second
side (L2) in the axial direction with respect to the second wall
(32). In this case, for example, even if an oil passage is formed
inside the second wall (32), this oil passage cannot be directly
connected to the end of the rotor shaft (26) on the second side
(L2) in the axial direction. In order to supply oil from the end of
the rotor shaft (26) on the second side (L2) in the axial direction
to the second oil passage (92), a connection oil passage needs to
be formed which connects the oil passage formed inside the second
wall (32) and the end of the rotor shaft (26) on the second side
(L2) in the axial direction. This tends to make the oil passage
configuration complex and also tends to increase the overall size
of the configuration as the connection oil passage needs to be
located so as to bypass members (e.g., the drive transmission
mechanism (2) etc.) disposed on the second side (L2) in the axial
direction with respect to the second wall (32). On the other hand,
in the structure for cooling the rotating electrical machine (MG2)
according to the present disclosure, as described above, oil can be
supplied from the supply oil passage (90) to the second oil passage
(92) through the first oil passage (91) and the third oil passage
(93). Accordingly, the oil passage configuration can be restrained
from becoming complex and an increase in overall size of the
configuration can be restrained even if the end of the rotor shaft
(26) on the second side (L2) in the axial direction is located on
the second side (L2) in the axial direction with respect to the
second wall (32) as in the above configuration.
A connection portion (90a) of the supply oil passage (90) may be
formed along a second wall (32) of the case (30) which is located
on a second side (L2) in the axial direction with respect to the
rotating electrical machine (MG2), the connection portion (90a)
being a part of the supply oil passage (90) which is connected to
the supplied portion (91a), and the second side (L2) in the axial
direction being an opposite side in the axial direction (L) from
the first side (L1) in the axial direction.
With the above configuration, as described above, not only the
third oil passage (93) is formed along the first wall (31) but also
the connection portion (90a) of the supply oil passage (90) is
formed along the second wall (32). It is therefore easy to
appropriately form these oil passages in the space where the walls
of the case (30) are placed. An increase in overall size of the
configuration can thus be restrained.
The supply oil passage (90) may be formed by using a tubular member
(43).
In order to directly connect the supply oil passage (90) and the
second oil passage (92), a branch portion from the supply oil
passage (90) to the second oil passage (92) needs to be formed.
This increases the number of connection portions between the supply
oil passage (90) and other oil passages. Typically, the larger the
number of connection portions between the supply oil passage (90)
and other oil passages is, the higher the machining accuracy and
mounting accuracy required for the supply oil passage (90) are. If
dimensional tolerance and mounting tolerance of the supply oil
passage (90) are increased in order to facilitate mounting of the
supply oil passage (90), oil is more likely to leak through the
connection portions. This problem tends to be significant when the
supply oil passage (90) is formed by using a tubular member (43) as
in the above configuration. However, in the structure for cooling
the rotating electrical machine (MG2) according to the present
disclosure, no branch portion from the supply oil passage (90) to
the second oil passage (92) needs to be formed. Accordingly, this
problem can be easily avoided.
A first rotating electrical machine (MG1) and a second rotating
electrical machine (MG2) may be accommodated in the case (30), the
second rotating electrical machine (MG2) being the rotating
electrical machine (MG2), and the structure for cooling the
rotating electrical machine (MG2) may further include: an oil
cooler (OC) provided in the supply oil passage (90); and a cooling
oil passage (94) through which oil for cooling the first rotating
electrical machine (MG1) flows, the cooling oil passage (94) being
an oil passage branching from a part of the supply oil passage (90)
which is located downstream of the oil cooler (OC).
With the above configuration, oil can be supplied from the supply
oil passage (90) not only to the first oil passage (91) but also to
the cooling oil passage (94). Accordingly, the oil passage for
cooling the first rotating electrical machine (MG1) and the oil
passage for cooling the second rotating electrical machine (MG2)
have a common part, whereby the oil passage configuration can be
restrained from becoming complex. With the above configuration, the
cooling oil passage (94) is formed so as to branch from the part of
the supply oil passage (90) which is located downstream of the oil
cooler (OC). Accordingly, oil cooled by the oil cooler (OC) can be
supplied to both the first rotating electrical machine (MG1) and
the second rotating electrical machine (MG2) to appropriately cool
the first rotating electrical machine (MG1) and the second rotating
electrical machine (MG2).
The oil pump (OP1) may be placed on a different axis from the
rotating electrical machine (MG2).
In the structure for cooling the rotating electrical machine (MG2)
according to the present disclosure, even if the oil pump (OP1) is
placed on a different axis from the rotating electrical machine
(MG2) (i.e., on a different axis from the second oil passage (92))
as in the above configuration, oil can be supplied from the supply
oil passage (90) to the second oil passage (92) through the first
oil passage (91) and the third oil passage (93) while restraining
the oil passage configuration from becoming complex.
A vehicle drive device (1) includes: the structure for cooling the
rotating electrical machine (MG2); an output member (4) drivingly
coupled to a wheel (W); and a drive transmission mechanism (2) that
transmits a driving force of the rotating electrical machine (MG2)
to the output member (4), and the oil pump (4) is driven by
rotation of the drive transmission mechanism (2).
With the above configuration, regardless of the drive mode of the
vehicle having the vehicle drive device (1) mounted thereon, the
oil pump (OP1) can be constantly driven while the vehicle is
moving. Accordingly, regardless of the drive mode, oil can be
supplied to the first oil passage (91) and the second oil passage
(92) to cool the stator (21) and the rotor (24) of the rotating
electrical machine (MG2).
The rotating electrical machine (MG2) may be disposed so as to
overlap the drive transmission mechanism (2) as viewed in the axial
direction (L).
In the case where the rotating electrical machine (MG2) is disposed
so as to overlap the drive transmission mechanism (2) as viewed in
the axial direction (L), the vehicle drive device (1) tends to be
increased in size in the axial direction (L) in the portion where
the rotating electrical machine (MG2) is disposed. In this respect,
in the technique according to the present disclosure, the third oil
passage (93) is formed along the first wall (31), whereby the
vehicle drive device (1) can be restrained from being increased in
size in the axial direction (L) in the portion where the rotating
electrical machine (MG2) is disposed. It is therefore easy to apply
the technique according to the present disclosure in the case where
the rotating electrical machine (MG2) is disposed so as to overlap
the drive transmission mechanism (2) as viewed in the axial
direction (L).
In the configuration in which the rotating electrical machine (MG2)
is disposed so as to overlap the drive transmission mechanism (2)
as viewed in the axial direction (L) as described above, the drive
transmission mechanism (2) may be disposed on an opposite side in
the axial direction (L) of the rotating electrical machine (MG2)
from the first side (L1) in the axial direction.
With the above configuration, the drive transmission device (2) can
be disposed at a position that less affects the configuration of
the third oil passage (93). This makes it easier to form the third
oil passage (93) along the first wall (31).
The structure for cooling a rotating electrical machine and the
vehicle drive device according to the present disclosure need only
have at least one of the effects described above.
* * * * *